Need help on this subject too! I have never had staggered setup on this car. Are there any advantages? What would a spacer do to a non-staggered?

dont use spacers if you can .. stagerred is basically wider rear tyre, so you get biiger patch on the road, more traction. with spacer you just pushing the wheels out. Looks same probably, but putting stress on suspension and so on. don't do it, get staggered.